I didn't understand the scene...

While I don't remember the exact expressions in the scene, I believe just seeing pretty, clean, friendly female faces again felt strange. Sledge doesn't mention any nurses in his book, but he writes about the sense of otherness when they returned to Pavuvu and saw relaxed, clean-shaven troops in neat uniforms, while they themselves were dirty and their uniforms even filthier.

Just finished reading that section of With The Old Breed (written by E. Sledge).

The sight of a woman on Pavuvu was such a shock to him, and many others, that he couldn't process it. It's not anger. It's more like disbelief. How could a pretty, young woman be here, on Pavuvu, just handing out drinks with a smile?

"You can't wear a vest with a vest. That's just tacky."

Eugene seemed like a thoughtful guy, and a nurse in that harsh environment felt like fake to him. As if some higher power would try to hide the reality from them, to somehow write off all the suffering and exhaustion.

At least that's what I thought of it.

Like other poster have said, it seemed like he saw something both otherworldly and alien in her. After the harrowing experience he s been through seeing this pretty, cheerful girl handing out lemonade was both a revelation and a slap in the face.

She had no business being there in his mind - both in her neat appearance and attitude - like she was giving drinks at some carnival, while he, for weeks or months saw nothing but dirt and death. His reaction to the other marine telling him "you've had you look, now move along" was a suiting reaction - "What the hell is going on here? Juice? Pleased to meet you? Move along? Where am I?"

Cognitive dissonance.

Its obvious he wanted to plant his tube steak in her donut